Water heater



Sept. 24, 1935. P. SWAN 2,015,296

WATER HEATER Filed March 5, 1934 F1 9 .5. INVENTOR.

Peter Ewa n, q

BY M

Patented Sept. 24, 1935 UNITED STATES amazes WATER HEATER Peter Swan,Portland, Oreg.

provement of facilities for cleaning the heat absorbing surfacesthereof.

A third object is the provision for easy repairs of thewater-circulating parts thereof without disturbance of the setting orrefractory linings which may be used with any of several methods offiring the same.

A fourth object is the conservation of floor space required for theoperation of such units.

Other objects and advantages of my invention will be apparent in thefollowing discourse wherein the significance of the reference charactersin the accompanying drawing, details of construction and manner ofoperation of a typical water boiler of my invention, and the particularadvantages thereof are explained.

Figure 1 represents a view of the complete water boiler in fragmentaryelevation and section.

Figure 2 represents a view of a horizontal section through the boilernear the upper part thereof showing the relationship in that aspect ofcertain essential heat-absorbing surfaces.

Figure 3 represents a view of a. typical watertube of the kindpreferably used in the con-' struction of certain elements of theboiler.

In detail, the body of the boiler is constructed of an outer cylindricalshell of steel I inside of which in spaced and concentric relationship,is another cylindrical shell 2 secured in the former by annular piecesas 3 welded to both the said shells at the top and bottom thereof in amanner to form a water-jacket extending the entire height of the saidbody and encompassing the contained chamber throughout its entirecircular extent.

Crates, or other firing means are disposed within the centrallycontained chamber at a convenient altitude to divide the said centrallycontained chamber into a combustion chamber and ash-pit respectively.Two doors 4 and 5, closing suitable communications to the saidcombustion space and ash-pit, give access for tending the fire.

The top of the combustion chamber is closed by a plate 6 of annular formloosely fitted within the upwardly extended outer shell 1 and supportedupon the upper extremity ,of the inner shell 2 and annular piece 3 in amanner to permit of the rotation of plate .6 upon. the said support.

The plate 6 is formed with an orifice l affording access to the interiorof the combustion chamber at whatever portion thereof the said orificeis disposed near by rotation of the plate ii. This orifice l is closedby a suitable lid 8 '5 conveniently removable.

A smoke outlet 9 providing communication between the said combustionchamber and the smoke pipe H3, is of cylindrical form rotatably mountedin the central opening of the plate 65 10 and is further provided withlateral, diametrically opposed perforations through which the pipebranches I! and I2 extend.

A layer of insulating substance I3, adhering to the plate 6, isdesirably provided to prevent the loss of heat at this place.

The top of the said water-jacket is tapped at I4 and pipes l5 and [6,extending upwardly and downwardly, connected thereto. The lower branchI6 is extended by means of conventional pipe-fittings through thewater-jacket but without communicating therewith to a point in thecombustion chamber where an upwardly extending pipe connection ll,disposed in alignment with the central axis of the combustion chambercommunicates with a water-tube unit l8 of special construction to bedescribed further on.

The top of the water-tube unit is is connected through the pipe is withthe pipes H and I2 extending laterally through the smoke outlet 9 asbefore described.

The usual relief valve and pressure or altitude gage 2i and 28respectively are fitted to the pipe In the pipe [5, before described, aperforated plug 22 is secured to provide a relatively smallcommunication between the uppermost part of the water-jacket tapped bythe pipe M and the pipe [2.

The water-tube unit [8 is composed of a central cylindrical element 23fitted with horizontally disposed partitions 24 and 25 both of which areperforated with relatively small holes indicated at 26 and 2?. Thesepartitions divide this cylindrical element into three chambers theuppermost and lowermost of which are tapped by series of angularlyseparated holes in staggered relationship. The middle chamber is tappedby two such series aligned respectively with those holes in theuppermost and lowermost chambers so that the two upper series of holesshall be in alignment and the two lower series of holes shall be alignedbut in staggered relationship tothe said two upper series of holes.

Each of these holes is connected to another hole situated on theopposite side of the horizontal partition nearest thereto by awater-tube in the form of a three-quarters portion of a complete turn ofan helix of which the tubes 23, 29, 3G, and 3! are typical and which areparticularly illustrated in Figure 3. Each of the said watertubes willthus extend from a point at one level on the cylindrical memberhelically to a point at another level angularly separated by ninetydegrees of are as illustrated in Figure 2.

The boiler is served by an outlet pipe 32 and a return pipe 33 which areconnected to a heating system or hot water storage tank in the usualmanner.

Considering the boiler to be connected to a hot water heating system orstorage tank and filled with water in the usual manner the operationthereof is as follows:

Cold water enters the lower part of the waterjacket through the pipe 33and absorbs heat from the adjacent ash-pit and body of fireprogressively as it rises in response to the difference in pressurecommon to the thermosiphon. During the process of heating certain smallquantities of dissolved air will be released from the wa ter in thejacket and rise to the top thereof. These small quantities of air orother gases accumulating in the upper part of the water-jacket willescape through the perforation in the plug 22 into the outlet 32 as willalso an inconsiderable quantity of warm water.

The greater volume of water will flow downwardly through the pipe l6 andthence enter the lower part of the water-tube unit 23 where it flowscentrifugally in the lowermost chamber to enter the lower ends of thehelical water-tubes as 30 and 3|. The flow of water is thence continuedthrough these helical tubes disposed symmetrically through thecombustion space to the middle chamber of the cylindrical element whereit flows first centripetally and laterally in a centrifugal directionimpelled as well by a whirling motion induced by the action of thehelical tubes to enter the lower end of the upper series of helicaltubes terminating in the upper part of the said middle chamber.

The water is thence carried outwardly and upwardly through the upperseries of helical tubes to different portions of the combustion spacefrom whence it returns to the uppermost chamher in the cylindricalelement where it flows centripetally to enter the pipe l9 through whichit is conducted to the pipe l2 and thence out through the system toreturn when cooled through the return pipe 33.

During the passage of the water through the helical tubes thetemperature thereof will be raised considerably and further quantitiesof dissolved air and other gases will be released into the centralchambers. Egress for these gases is provided for by the perforations inthe horizontally disposed partitions 24 and 25, effectively preventingair-binding of the water-tubes and consequent overheating thereof.

Now it will be especially observed that the height of the wholeapparatus as related to the heat absorbing capacity thereof ismaterially lessened by the method of construction employed and inconsequence, the total area of exposed radiating surfaces through whichheat losses may occur is very appreciably reduced. Again the forcesactuating the circulation of water are relatively reduced and larger andmore substantial pipe sizes may be employed without serious loss ofefliciency.

The form of the helical water-tubes is of special importance. This formprovides for a more nearly uniform distribution of the heat absorbingsurfaces because of the fact that the most nearly centrally disposedportions thereof are virtually radial while the outer portions or loopsare disposed with the greatest linear magnitude thereof near the largestcircumference of the combustion space. This is particularly apparentupon inspection of the Figure 2.

In another manner of consideration, this form of water-tube provides forthe greatest radius of curvature thereof throughout the whole extent andthus provides for a minimum of frictional resistance to the passage ofwater theret-hrough. It again provides for a very uniform disturbance ofthe water in passage therethrough to effect the contact of more portionsof water with the heating surfaces so that the water may be heated bydirect contact with the metal of the tubes rather than throughconduction in the water itself or normal processes of convectionunassisted by mechanical action As is well understood, the greatestefficiency is to be attained only by providing for as great atemperature differential between the gases of combustion and the waterto be heated as possible. It will be understood that this effect isaccomplished to a very high degree in the heater of my invention inwhich the water is conducted progressively from the parts of lowest tothe parts of highest temperature.

Besides the very high operating efiiciency, the water-boiler of myinvention embodies many other unique advantages in combination therewith.

The lid 8 may be easily removed and access had to all parts of thewater-tubes for cleaning by revolving the plate 6. This plate is alsoconveniently entirely removed for the replacement of the water-tube unitor other service requiring access to the full combustion chamberdiameter. The method of removal of this plate is as fol lows: The upperpipe-union is broken and the fittings unscrewed to free the smoke outlet9 which may be then removed. This done, the plate 6 may be lifted outgiving clear access to the Whole of the combustion chamber. If it isnecessary to remove'the water-tube unit, this may be accomplished bybreaking the lower union and unscrewing the horizontal length of pipetherefrom when the unit will be free to lift out.

It will be obvious that all of these services can be accomplishedwithout disturbing the setting of the boiler or the refractory lining ofthe firebox. Neither is it necessary to disturb the outlet or returnpipe lines further than to drain the water therefrom.

From a study of the Figures 1 and 2 it will be further apparent that thewater-tube unit as constructed of helical water-tubes constitutes a kindof screw directing the flow of the products of combustion in a spiralmotion thereby causing the actual contact thereof with the water-tubesin smaller and hotter portions than is common in the case of boilersconstructed with rectilinear flues wherein portions of very hot gasesmay be conducted therethrough without actual contact with the heatingsurfaces from which the same are insulated by already cooled portions.

Gases moving in simple translatory motion are relatively undisturbed;portions thereof centrally contained remaining so. On the other hand,gases moving in spiral courses are constantly disturbed and the relativepositions of various portions thereof are constantly changing. This isthe result accomplished in the heater of my invention to the end thatthe greatest possible proportion of the products of combustion may beurged into actual contact with heat absorbing surfaces inside of whichflow currents similarly agitated to urge the coolest portions thereofinto actual contact with the heating surfaces.

In addition certain manufacturing advantages inherent in thisconstruction are of great importance. It will be obvious that themanufac ture of helical Water tubes can be more easily accomplished thanany other curved or bent form. The tubes in my boiler may be made incontinuous length and cut thereafter into three-quarter turn lengthsdescribed. The whole assembly being admirably adapted for weldingprocesses, obvious'economies of labor are provided for.

The total advantages of my invention provide high operatingefiiciencies, facility of maintenance and repair and economies of Weightand manufactured cost of great value.

What I claim is:

1. A water boiler comprising, a water-jacket contained between twoshells housing a fire box and combustion chamber, a water-tube unitdisposed within said combustion chamber intercommunicating meansconnecting the upper part of said water-jacket with the lower part ofsaid water-tube unit, an inlet and an outlet communicating withthe lowerpart of said water-jacket and the upper part of said water-tube unitrespectively, a communication of relatively small capacity connectedwith the upper part of said water-jacket and the said outlet, and asuitable closure for the top of said combustion chamber formed with asuitable smoke outlet wherein the said water-tube unit is constructed ofa series of vertical axially aligned cylindrical chambers the lowermostand uppermost of which are formed with an inlet and outlet respectively,and a series of three-quarterturn helical water-tubes arranged insymmetrical groups about said chambers and connected at opposite ends toadjacent said chambers at places angularly separated by ninety degreesof arc, the said cylindrical chambers being connected together by anadditional connection of relatively small capacity to provide egress foraccumulated quantities of gases.

2. A water boiler comprising, a water jacket contained between twoshells housing a fire-box, a water-tube unit disposed over said firebox, intercommunicating means connecting the upper part of said waterjacket with the lower part of said water-tube unit, an inlet and anoutlet communicating with the lower part of said waterjacket and theupper part of said water-tube unit respectively and a suitable housingfor said Watertube unit disposed upon the said water jacket and providedwith a suitable smoke outlet wherein the said water-tube unit isconstructed of a series of vertical axially aligned cylindrical chambersthe lowermost and uppermost of which are formed with an inlet and outletrespectively and a series of three-quarter-turn helical water-tubesarranged in symmetrical groups about said chambers and connectedratopposite ends to adjacent said chambers at places angularly separated byninety degrees of arc, the said cylindrical chambers being furtherconnected together by communications of relatively small capacity toprovide egress for accumulated gases.

3. A water tube unit for water boilers comprising, a vertically disposedcylinder containing a series of superposed chambers separated byhorizontally disposed partitions, a series of helical water-tubesconnecting said adjacent chambers, and relatively small ports connectingsaid adjacent chambers together through said horizontal partitions toprovide for the egress of gaseous accumulations. I

4. A water tube unit for water heaters comprising, a verticallydisposedcylinder containing a series of superposed chambers separated byhorizontally disposed partitions the lowermost and uppermost of whichare formed with an inlet and outlet respectively, a series ofthree-quarter turn helical water-tubes connecting adjacent said chambersarranged in symmetrical groups about said chambers at places angularlyseparated by ninety-degrees of arc, and relatively small portsconnecting said adjacent chambers together through said horizontalpartitions to provide for the egress of gaseous accumulations.

PETER SWAN.

